package com.sy.demo.interceptor;

import org.aspectj.weaver.ast.Var;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * @author songyi
 * @date 2020/6/17 0017 21:21
 * @description 自定义拦截器
 */
public class MyIntercepter implements HandlerInterceptor {

    /**
     * 会在handler方法业务逻辑执行之前执行
     * 往往在这里完成权限校验工作
     * @param request
     * @param response
     * @param handler
     * @return  返回值boolean代表是否放行，true代表放行，false代表中止
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        String username = (String) session.getAttribute("username");
        if ("admin".equals(username)) {
            System.out.println("有权限访问");
            return true;
        } else {
            System.out.println("没有权限访问");
            response.sendRedirect("/login.jsp");
            return false;
        }
    }


    /**
     * 会在handler方法业务逻辑执行之后尚未跳转页面时执行
     * @param request
     * @param response
     * @param handler
     * @param modelAndView  封装了视图和数据，此时尚未跳转页面呢，你可以在这里针对返回的数据和视图信息进行修改
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyIntercepter postHandle......");
    }

    /**
     * 页面已经跳转渲染完毕之后执行
     * @param request
     * @param response
     * @param handler
     * @param ex  可以在这里捕获异常
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyIntercepter afterCompletion......");
    }
}
